@Prince

The hole of silencer at the engine head is common for all pulsars....!!! It exists for my 2009 model exhaust(Pulsar 150 2005model)....!!!!

The hole diameter is not that much big in the pics you posted...!! It also doesnt show any corrosion around the hole... Am i right..??? I mean the hole is perfectly round without corrosion...!!!

In my old chrome silencer the corrosion was very high and the holes became uneven, so i had changed it to new one...!!

I too had a similar doubt for that hole.. i even twisted throttle(raised at carburettor ) to know if it emit any air/ smoke as in the case of outer holes...!! But no pressured air/ smoke/ dust/ soot is coming from that hole...!!!!!

But from the pic you have posted, we can see some soot adhered to bolt...!!!! It is raising new doubts...!!!

so you mean to say "hole is present in all bikes but under normal.circumstances no smoke comes out of it" again this is news. coz my bike is making phat phat noise because smoke is coming from that hole.

GUYS ... ALL THOSE WHO HAVE A PULSAR PLZ CHECK AND REPORT BACK-DOES YOUR BIKE EMIT SMOKE FROM THIS HOLE DISCUSSED HERE.

Prince I ran a google search. Apparently it seems the hole is called a weep hole to drain of any water. Some bikes may have some may not. I m not very convinced about this though.

I came across this link Exhaust header pipe leak - Kawasaki Vulcan Forum : Vulcan Forums the guy seems to have a similar problem on his Vulcan. He can find exhaust leaking from the hole. Which means it is not supposed to. From what he has posted, it seems the header is sort of a double containment unit with a liner inside. I am not very sure of this as I have nt seen a header dismantled. Moreover, I ll check my Avenger tomorrow to see if a hole like that exists. also I ll see if I can find any pulsars in my locality and check the header.

EDIT: Came across another forum where a guy complaining the same thing. Smoke coming from the weep holes..

@vibbs: thanks for that link, that had a similar problem but unfortunately nobody gave him a reply. similar to that guy, even i had this problem of somewhat rough or uneven idle. my bike previously used to idle perfectly at 1200 rpm, now it idles at 1000 rpm.i have adjusted the idle many times to 1500rpm but every time it automativally returns to 1000 rpm. but i dont associate this idle problem with this hole as i know there is a fault in my carb, the diaphram and slider piston (black color) has worn out and due to that i have a sluggish mid-range. i will be replacing these two parts on sunday. so i dont associate my idle problem.with.this hole. just mentioned it since that guy also had this problem. but i dont think this idle problem is because of.this hole coz both sluggish mid range and idle problems i have experienced in past also and were due to these two faulty parts in my carb and earlier also were solved by replacing.these two parts. so just mentioned it here.

AND

i dont think it is a weep hole for water draining as there is not point in providing a water drain hole so high. ideally all water drain holes should be as low as possible, preferably at the bottom.

anybody knows something about back pressure ?

No , this can't be a weep-hole by any means ... those are present at the lowest bottom of the exhaust so that any fluid entered there may drain . I'm also agreed with Psr'Jee that a hole like this has no place on the bend pipe and should be considered a defect .... but Prince and others has already confirmed that it's an usual feature on most pulsar bent-pipes ... then it must be an usual thing here . Something to do with conforming to BS exhaust gases limits maybe ? By letting some of it out before it reaches the end of tail-pipe and detected by regulation emission-tests ??
It must be something peculiar to the pulsars which only Bajaj's engine designers may be able to explain the engineering logic to . No , service engineers can't be expected to be privy to this kind of info .... they are hardly able to diagnose the usual day-to-day problems .

Exactly, a hole for draining water should not be as high as it is in your case. One thing I m pretty sure is that, you should not be having any exhaust leaking from that hole in any case. An exhaust leak will gradually cause the hole to get bigger and bigger. That again brings us back to the question why the hole in first place. Let me search around more on the net about the topic. Will let you know if I stumble across something.

EDIT: @Prince, It could be a double walled exhaust pipe, like I assumed in my previous post, with an air gap in between. The hole is would only be on the outside pipe. Smoke leaking from the hole indicates a cracked inner pipe. Check this link http://www.hussgroup.com/metpela/en/...wall-pipes.php it speaks about double walled pipes for exhausts. Many motorcycles have it but I m not sure if Pulsar too has the same. You can try inserting a pin or something inside the hole to check if there is another pipe inside.

@ vibbs: dude,.again thanks for another informative link.

so i think it is not a weep hole for water.

one more thing, as you said exhaust gases should not leak through any holes in exhaust.

BUT,

on my bike exhaust gases leak through even the hole at the bottom of exhaust supposedly for water drain.

AGAIN I REQUEST ALL PULSAR OWNERS ON XBHP TO CHECK AND REPORT BACK IF THEIR BIKE'S EXHAUST ALSO EMOT SMOKE FROM ALL HOLES i.e. THE TOP HOLE BEING DISCUSSED HERE AND THE BOTTOM MOST HOLE.

apart from back pressure doubt, what pinaki ji has raised also holds ground, designers sometimes do resort to cheap tactics to pass some stringent law, which otherwise they are finding difficult.to pass.

guys more info required to solve this mystery.

@princesirohi

Sir, since your idle's dropping I'd assume that you're running rich.

yes i know i am running rich, but thata another issue.

searched the internet, made some really good use of internet and found--
one more biking forum.discussing same thing--


another biking forum discussing somewhat similar thing--


now this link can give some real usefull food for though--


one of the possible problem arising out of such a leak--


another thing i learned is if there is a leak very near to cylinder head as in my case, it can also fry out exhaust valves.

Ha...

Here is the whole hardware....!!!!

My bikes silencer is 2009 model original silencer (Since tthe silencer didnt get any problem nor it was opened nor the engine was opened...!!!!)

I am aware that most of pulsar owners after getting their chrome silencers damaged most people are opting for market silencers which are similar to present original ones but are duplicate..!! we can find it by absence of exhaust tec chamber downside and ExhausTEC embossing on chrome heat guard..!!!

@Prince.. may i know have you opted for original silencer...??? (Excuse me for doubting you.. )

Close pic of Hole of silencer at engine head



side view pic showing no signs of smoke/ soot on bolt


GUYS... I have found that there is another metal layer inside that hole...!! i tried to insert a saftey pin end...!!! to my surprise it resisted to go not more than quarter cm...!!!! Here is the pic...!!!!

yes, my exhaust is original.

i will check my exhaust holes by imserting pin but can you tell does hour exhaust emit smoke from these holes.

the links given in my earlier post give a lot of info about these double walls and holes.

In your first pic I think the inner wall is visible even. Then I guess we get the root of the problem. In Prince's case I guess the inner wall is leaking either due to a crack, or from the joint which connects to the engine (I have not seen how it connects with the engine, but I m assuming that, since it may be a double wall pipe the connection would be through the inner wall). In case it is a crack on the inner wall, I guess it is better to get the header pipe changed. Welding the hole wont work because, the idea of having a double wall is to provide some sort of insulation as the air gap between the pipes acts as an insulator. Welding the outer hole might not solve the root cause and the exhaust will keep on leaking into the space between the walls. You may not get the sound that you are getting now, but the outer wall may not be built to handle exhaust gas and may eventually corrode or even get excessively hot depending on the amount of exhaust leaking out.
Secondly the holes must be acting as a tell tale hole too. Incase of damage to the inner wall you can see smoke coming out from the holes and you know something is wrong. Now if we weld the outer holes off, we dont know what is the condition of the inner wall. If it gets too much damaged, it may melt off and fold away and bike may stall as somebody pointed out in one of those links shared by Prince.

@Prince they are some good links. Whole lot of information it seems, not checked all, will do so. Thanks for sharing here.

yes, i chechek the hole with a pin. there is an inner wall and the pin didn't go too much into the hole.

will dismantle the exhaust tommorrow and try to see what is wrong.

till then a request to other pulsar owners to check if there holes blow smoke or not.?

it seems not many people are either interested in discussing this or does not know much about these holes.

will check tommorrow by dismantling the exhaust and report back.

^^ Well, me being a none pulsar guy have no knowledge about these 'holy' () silencers but do want to know about the topic and keeping myself up-to-date with the thread.
So keep sharing whatever you're coming across.